package com.example.demo.controller;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartHttpServletRequest;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.util.List;


@RestController
public class FileController {
    private static  final  String filePath="/Downloads/";
    private static  final Logger log =  LoggerFactory.getLogger(FileController.class);

    @RequestMapping("upload")
    public String upload(@RequestParam("file")MultipartFile file){
        try{
            if(file.isEmpty()){
                return "文件为空";
            }
            //获取文件名
            String fileName = file.getOriginalFilename();
            log.info("上传的文件名为："+fileName);
            String path = new File(filePath).getAbsolutePath()+ "/" + fileName;
            File dest = new File(path);
            //检测是否存在目录
            if(!dest.getParentFile().exists()){
                dest.getParentFile().mkdirs();//新建文件夹
            }
            file.transferTo(dest);//文件写入
            return "上传成功,"+path;
        }catch (IllegalStateException e){
            e.printStackTrace();
            log.info(e.getMessage());
        }catch (IOException e){
            e.printStackTrace();
            log.info(e.getMessage());
        }
        return "上传失败";
    }

    @PostMapping("/batch")
    public String handleFileUpload(HttpServletRequest request) {
        List<MultipartFile> files = ((MultipartHttpServletRequest)request).getFiles("file");
        MultipartFile file = null;
        BufferedOutputStream stream = null;
        for (int i = 0; i < files.size(); i++) {
            file = files.get(i);
            if(!file.isEmpty()){
                try {
                    byte[] bytes = file.getBytes();
                    stream = new BufferedOutputStream(new FileOutputStream(new File(filePath+file.getOriginalFilename())));
                    stream.write(bytes);
                    stream.close();
                } catch (Exception e) {
                    e.printStackTrace();
                    stream = null;
                    return "第"+i+"个文件上传失败==>"+e.getMessage();
                }
            }else {
                return "第"+i+"个文件上传失败,因为文件为空";
            }
        }
        return "上传成功";
    }

    @GetMapping("/download")
    public String downloadFile(HttpServletResponse response){
        String fileName = "龙猫.jpg";
        if(fileName !=null){
            //设置文件路径
            File file = new File(filePath+fileName);
            if(file.exists()){
                response.setContentType("application/force-download");//设置强制下载不打开
                response.addHeader("Content-Disposition","attachment;fileName="+fileName);//设置文件名
                byte[] buffer = new byte[1024];
                FileInputStream fis = null;
                BufferedInputStream bis = null;
                try{
                    fis = new FileInputStream(file);
                    bis = new BufferedInputStream(fis);
                    OutputStream os= response.getOutputStream();
                    int i = bis.read(buffer);
                    while (i!=-1){
                        os.write(buffer,0,i);
                        i=bis.read(buffer);
                    }
                    return "下载成功";
                }catch (Exception e){
                    e.printStackTrace();
                }finally {
                    if(bis!=null){
                        try{
                            bis.close();
                        }catch (IOException e){
                            e.printStackTrace();
                        }
                    }
                    if(fis != null){
                        try {
                            fis.close();
                        }catch (IOException e){
                            e.printStackTrace();
                        }
                    }
                }
            }
        }
        return "下载失败";
    }
}
